let arr = [5, 4, 3, 1, 2, 6, 9];
arr.forEach(item => {
  console.log(item); // 依次输出 5, 4, 3, 1, 2, 6, 9
});
let arr1 = [
  {
    name: 'zg',
    age: 18
  },
  {
    name: 'kobe',
    age: 35
  },
  {
    name: 'lucy',
    age: 22
  },
];
arr1.forEach(item => {
  console.log(item);
  /* 依次输出
  {name: 'zg', age: 18}
  {name: 'kobe', age: 35}
  {name: 'lucy', age: 22}
  */
});
